Feeling Pessimistic About The Future Of Southwestern Forests

Friend John and myself have been watching these Southwestern forest fires with an increasing sense of dread, worried about the ultimate fate of these arid forests:

John starts the conversation:

New Mexico. New fires every day. Will it become a barren desert in a generation? I wonder... I did read a report from the Gila burn area that there is still vegetation left in some areas. And I hope that some of the ancient trees survived. Actually, I'm a bit tempted to go back next year and see what the fire has wrought. I guess it's kind of like seeing an automobile accident from a distance and rushing over to get a good look.

I reply:

I remember back in Corrales days, in the mid-60’s, when we had a fire near the house, and I was surprised how quickly and with what force the vegetation came back. A lot depends, I think, on how much support the new vegetation gets from rainfall.

I also remember spending 3 months at the USFS Ft. Valley Experimental Station, about 12 miles NW of Flagstaff, AZ, in the winter of 1985-86. There was one well-recognized fire scientist on staff (Dr. Richard Tinus) who pointed out to me a problem with the forest all around us. Apparently, weather conditions were perfect in the spring of 1919 for ponderosa pine seedlings to take root, so clusters of seedlings all took root together. Sixty-six years later, you could tell where every, single pine cone hit the forest floor that spring, because sickly trees, starved of resources and thinner than your wrist, were clustered everywhere at those points. Instead of forming open parklands, the ponderosa pine forests were more like crowded thickets. You could tell this was a bad story that would end up only in one way: a nasty forest fire. No forest management regimen would ever have the resources to do what was necessary, and clear the thickets out before a fire swept through.

I’m not familiar with the Gila, but it wouldn’t surprise me in the Flagstaff problem was widespread enough to include it too. The sickness may have been widespread. If so, then there was only one way for the story to end.

Nevertheless, when an entire forest is burnt, as has happened with last year’s Wallow fire, the 2003 Rodeo-Chideski Fire, and now this grotesquely-large fire, then the entire area is launched on a new trajectory. To retain the forests you need enough of the older trees, so as to form something approaching a canopy. Some of these forests may be Ice Age relicts (it’s hard to believe Kit Carson spent his days in the Gila taking out so much beaver), and no longer a good match with the present age, and so maybe will spring back this time with an entirely-different sort of vegetation: pinon-juniper, for example, or manzanita thickets, or grasslands. Ponderosas could disappear from places. Maybe a lot of places.

I sure hope the monsoons this year are generous (but not so generous as to cause flooding).

John replies:

I think the forest of the Southwest have been changing for some time now, and those changes were not--at least until recently--human caused. The last white pine in Chaco Canyon (on the rim) died in 1927 according to accounts of period archaeologists there. A rancher told me in the late 1970's that the last of the white pines in the Ladrones had recently died off.

As to the Gile, I did not notice any clusters of relatively young ponderosa pines, but since I was not aware of that 1919 growth spurt perhaps I just did not see it. Overall my impression of the forest there was that it seemed fairly healthy but dry. There was a huge amount of fallen timber which had accumulated over many decades. I would presume this was the primary fuel for the fire. As you may recall from the Pecos Wilderness there is an equally large amount of deadfall there too. My guess is that the wetter conditions of that area have prevented widespread wildfires there in recent memory. But as the climate continues to become more arid all across the region I believe that will change. My guess is that it is just a matter of time--and probably not much time--until the Pecos suffers the same fate as the Gila.

I have heard that there was a major die off of the pinons in northern New Mexico in the last few years. That would fit into a pattern of pinon forest being replaced by junipers. It will take a number or years to determine if pinons will replace the tall pines of the higher elevations.

I reply:

Here’s a grab-bag of observations….

I know they had a mass die-off of trees on the southern flank of the Jemez Mountains before the recent big Bandelier fire (Las Conchas, I think they call it). I had heard it was pine beetle infestation, accelerated by drought, but I’m fuzzy on details, since a lot of that vegetation would have been juniper too, not just pinon, so I’m confused. I’m also worried about the forests SW of Denver – also dry, and subject to human-caused fires in recent years.

I remember seeing before-and-after pictures of the Reno, NV area, from the Gold Rush days, and today, and being really surprised how much juniper there is in these areas today. In north-western areas of the Great Basin, juniper is almost like a weed, and spreading rapidly. I have a book on the natural history of the Great Basin, and they point out that there are mountain ranges in southern Idaho, SW Oregon, and NW Nevada where pinon/juniper forests should be able to grow, but don’t. They conclude that the natural vegetation of the area is lagging behind climate change, and eventually will support such forests. Maybe as climate warms, the vegetation belts will just shift north.

I’ve also seen old pictures from the Albuquerque area, and been really surprised how stark the old pictures look. I’m assuming that goats and cows from the oldtimers had denuded the hills near Albuquerque, and that things are actually more lush there today than they were 100 years ago. I’ve also walked near the Rio Grande in Albuquerque fairly-recently and been surprised that, despite the anthropogenic chaos, that four-winged saltbush, an alkaline-loving desert-adapted plant, seems to be spreading from places where it was 40 years ago. Plus, without annual flooding from the river, the cottonwood groves continue to age and die. It may signal desertification of the entire area, or it may just signal further changes.